Why isn't my shower getting hot?

VfM4meplse

Just that really.

The thermostat on my tank is set to a balmy 70 degrees C and the water coming from the sink and bath taps is suitably hot, but for some reason the water from the overhead shower never gets above lukewarm. I've tested the temperature control on the shower unit itself, but that seems to make no difference whatsoever. The overhead shower is powered by an electric pump and the flow is strong, although I can't tell whether this is gravitational and good luck, or down to the pump itself. (There is a separate pump for another power shower in the house, this works fine but quite frankly uses so much water that lovely as it is, its not something I want to use daily).

Am I right in thinking there must be a separate switch somewhere to turn the electric shower on? Presumably a switch would allow for both temperature and flow? What should I be looking for?? Otherwise I guess I'm stuck with getting a handheld shower for the bath taps, not an option I'm keen on.

TIA

VfM4meplse

Just tested again. The pump is definitely working because I can hear it every time it I turn it on. But the water remains the same - lukewarm at one extreme end of the setting, and cold-lukewarm at the other extreme. The thread on the temperature control valve seems fine though. The valve looks a bit like this, if it helps?

Browntoa

This thread suggests cleaning the thermostatic valve

http://www.diydoctor.org.uk/forums/thermostatic-valve-on-shower-problem-t10464.html

Although it does seem to be a regular problem with that brand

Head_The_Ball

Is this a newly installed shower or a new problem with a previously working shower?

Is the pump a twin chamber pump boosting both hot and cold water? Perhaps the hot side is failing so it is pumping mostly cold and very little hot.

Alternatively perhaps the thermostat in the shower control has failed.

Browntoa

This one suggesting too high pressure

https://www.ukplumbersforums.co.uk/threads/bristan-mixer-cartridge-troubles.4724/

VfM4meplse

Thanks both.

Head_The_Ball wrote: »

Is this a newly installed shower or a new problem with a previously working shower?

The shower is inherited. I get the impression that the bath was used here, rather than the shower itself as the head was old and congested (I managed to replace this, at least!) so perhaps the previous owners knew? Makes sense given that the other one is state of the art. Not that it matters - its my problem to deal with now. From the advice given it looks like solving this problem will be by testing and excluding.

Head_The_Ball wrote: »

Is the pump a twin chamber pump boosting both hot and cold water? Perhaps the hot side is failing so it is pumping mostly cold and very little hot.

Re: suggestions about pressure levels, how would I be able to tell? Looks like one chamber to me, two slim-ish pipes which I assume are for hot and cold, and one broader one that I guess is the where the water enters the system. Can't see any controls on either. But am also mindful that dabbling might not be a good idea given that I am unskilled in this area.

Head_The_Ball wrote: »

Alternatively perhaps the thermostat in the shower control has failed.

Again, how would I be able to tell? Is a plumber necessary? I'm not scared to admit that I don't have a clue